Color uniformity correction of display device

Abstract

Disclosed are techniques for improving the color uniformity of a display of a display device. A plurality of images of the display are captured using an image capture device. The plurality of images are captured in a color space, with each image corresponding to one of a plurality of color channels. A global white balance is performed to the plurality of images to obtain a plurality of normalized images. A local white balance is performed to the plurality of normalized images to obtain a plurality of correction matrices. Performing the local white balance includes defining a set of weighting factors based on a figure of merit and computing a plurality of weighted images based on the plurality of normalized images and the set of weighting factors. The plurality of correction matrices are computed based on the plurality of weighted images.

What is claimed is: 
     
       1. A method of improving a color uniformity of a display of a wearable device, the method comprising:
 capturing a plurality of images of the display using an image capture device, wherein the plurality of images are captured in a color space, and wherein each of the plurality of images corresponds to one of a plurality of color channels; 
 performing a global white balance to the plurality of images to obtain a plurality of normalized images each corresponding to one the plurality of color channels; 
 performing a local white balance to the plurality of normalized images to obtain a plurality of correction matrices each corresponding to one of the plurality of color channels, wherein performing the local white balance includes, during each of multiple iterations through a loop using the plurality of normalized images:
 defining a set of weighting factors based on a figure of merit; 
 computing a plurality of weighted images based on the plurality of normalized images and the set of weighting factors; and 
 computing the plurality of correction matrices based on the plurality of weighted images; and 
 
 after computing the plurality of correction matrices and while the wearable device is being worn by a user:
 correcting a video sequence to be displayed at the wearable device using the plurality of correction matrices; and 
 displaying the corrected video sequence at the display. 
 
 
     
     
       2. The method of  claim 1 , wherein the figure of merit is at least one of:
 an electrical power consumption; 
 a color error; or 
 a minimum bit-depth. 
 
     
     
       3. The method of  claim 1 , wherein defining the set of weighting factors based on the figure of merit includes:
 minimizing the figure of merit by varying the set of weighting factors; and 
 determining the set of weighting factors at which the figure of merit is minimized. 
 
     
     
       4. The method of  claim 1 , wherein the color space is one of:
 a CIELUV color space; 
 a CIEXYZ color space; or 
 a sRGB color space. 
 
     
     
       5. The method of  claim 1 , wherein performing the global white balance to the plurality of images includes:
 determining target illuminance values in the color space based on a target white point, wherein the plurality of normalized images are computed based on the target illuminance values. 
 
     
     
       6. The method of  claim 5 , wherein the plurality of correction matrices are computed further based on the target illuminance values. 
     
     
       7. The method of  claim 1 , wherein the display is a diffractive waveguide display. 
     
     
       8. A non-transitory computer-readable medium comprising instructions that, when executed by one or more processors, cause the one or more processors to perform operations comprising:
 capturing a plurality of images of a display of a wearable device using an image capture device, wherein the plurality of images are captured in a color space, and wherein each of the plurality of images corresponds to one of a plurality of color channels; 
 performing a global white balance to the plurality of images to obtain a plurality of normalized images each corresponding to one the plurality of color channels; 
 performing a local white balance to the plurality of normalized images to obtain a plurality of correction matrices each corresponding to one of the plurality of color channels, wherein performing the local white balance includes, during each of multiple iterations through a loop using the plurality of normalized images:
 defining a set of weighting factors based on a figure of merit; 
 computing a plurality of weighted images based on the plurality of normalized images and the set of weighting factors; and 
 computing the plurality of correction matrices based on the plurality of weighted images; and 
 
 after computing the plurality of correction matrices and while the wearable device is being worn by a user:
 correcting a video sequence to be displayed at the wearable device using the plurality of correction matrices; and 
 displaying the corrected video sequence at the display. 
 
 
     
     
       9. The non-transitory computer-readable medium of  claim 8 , wherein the figure of merit is at least one of:
 an electrical power consumption; 
 a color error; or 
 a minimum bit-depth. 
 
     
     
       10. The non-transitory computer-readable medium of  claim 8 , wherein defining the set of weighting factors based on the figure of merit includes:
 minimizing the figure of merit by varying the set of weighting factors; and 
 determining the set of weighting factors at which the figure of merit is minimized. 
 
     
     
       11. The non-transitory computer-readable medium of  claim 8 , wherein the color space is one of:
 a CIELUV color space; 
 a CIEXYZ color space; or 
 a sRGB color space. 
 
     
     
       12. The non-transitory computer-readable medium of  claim 8 , wherein performing the global white balance to the plurality of images includes:
 determining target illuminance values in the color space based on a target white point, wherein the plurality of normalized images are computed based on the target illuminance values. 
 
     
     
       13. The non-transitory computer-readable medium of  claim 12 , wherein the plurality of correction matrices are computed further based on the target illuminance values. 
     
     
       14. The non-transitory computer-readable medium of  claim 8 , wherein the display is a diffractive waveguide display. 
     
     
       15. A system comprising:
 one or more processors; and 
 a non-transitory computer-readable medium comprising instructions that, when executed by the one or more processors, cause the one or more processors to perform operations comprising:
 capturing a plurality of images of a display of a wearable device using an image capture device, wherein the plurality of images are captured in a color space, and wherein each of the plurality of images corresponds to one of a plurality of color channels; 
 performing a global white balance to the plurality of images to obtain a plurality of normalized images each corresponding to one the plurality of color channels; 
 performing a local white balance to the plurality of normalized images to obtain a plurality of correction matrices each corresponding to one of the plurality of color channels, wherein performing the local white balance includes, during each of multiple iterations through a loop using the plurality of normalized images:
 defining a set of weighting factors based on a figure of merit; 
 computing a plurality of weighted images based on the plurality of normalized images and the set of weighting factors; and 
 computing the plurality of correction matrices based on the plurality of weighted images; 
 
 after computing the plurality of correction matrices and while the wearable device is being worn by a user:
 correcting a video sequence to be displayed at the wearable device using the plurality of correction matrices; and 
 displaying the corrected video sequence at the display. 
 
 
 
     
     
       16. The system of  claim 15 , wherein the figure of merit is at least one of:
 an electrical power consumption; 
 a color error; or 
 a minimum bit-depth. 
 
     
     
       17. The system of  claim 15 , wherein defining the set of weighting factors based on the figure of merit includes:
 minimizing the figure of merit by varying the set of weighting factors; and 
 determining the set of weighting factors at which the figure of merit is minimized.